Protecting unit for oil filled submergible motors



A ril 6, 1954 A. ARUTUNOF F PROTECTING UNIT FOR OIL FILLED SUBMERGIBLEMOTORS Filed June 25. 1952 INVENTOR lrmazkjruzuno/j ATTORNEY PatentedApr. 6, 1954 PROTECTING UNIT FOR OIL FILLED SUBMERGIBLE MOTORS ArmaisArutunoff, Bartlesville, kla., assignor to Reda Pump Company,Bartlesville, 0kla., a corporation of Delaware 7 Application J une 23,1952, Serial No. 295,054

8 Claims.

This invention relates to improvements in a protecting unit for oilfilled; submergible, elec- 1 tric motors used in connection with liquidpumping apparatus and although adaptable to various pumping operations,is primarily directed to a protecting unit for centrifugal pumpingassemblies designed for use by owners of farms, subur ban acreage, andsmall industries.

With pumping asemblies of the type Where the electric motor is submergedin a well and operably connected to the lower end of the casing whichhouses a coaxial pumping unit, an oil filled lubricating and protectingunit or reservoir is usually interposed between the pumping unit and themotor, such for example, as those illustrated and described in my priorPatent No. 2,569,741. As explained in that patent, due to the normalexpansion and contraction of the oil in the motor and motor protectingunit, resulting from the starting and stopping of the motor, there is atendency for the surrounding well fluid to leak into the protecting andlubricating reservoir and ultimately to find its way along the motorshaft to the motor unit. Hence, it is necessary to a successfuloperation of the system, to provide some means for insuring against theentrance of damaging moisture into the motor structure, two embodimentsof such means being illustrated and described in my said former UnitedStates patent.

The present invention operates on the same basic principle as thatdisclosed in said former patent and was designed both for use as thesole protecting unit, in generally similar pumping apparatus, or as anauxiliary protecting unit for use in connection with a breather unit ofthe type described in my said former patent.

The principal object of the present invention is to provide a protectingunit for attachment to the lower extremity of the oil-filled motorcasing of a submergible pump assembly, and comprising a collapsiblebreather diaphragm, composed of rubber-like material, surrounded bytransformer oil or the like and adapted to equalize pressure between theoil in the motor assembly and the water or other fluid in the well inwhich it is submerged.

A further object of the invention is to provide a protecting unit ofthis type, having a wicketlike frame or support for the diaphragm, comprising the breather and adapted to prevent the complete collapse of thelatter, so as to maintain a normally fixed reserve capacity in thesurrounding reservoir or lubricant containing por tion of the casing,and to allow for breathing when the motor is initially started andstopped.

A still further object of the invention is to provide a protecting unitof the character described, which is extremely simple in constructionand may easily be installed in connection with conventional submergiblepumping assemblies, without requiring any major alterations.

With the above and other objects in view which will appear as thedescription proceeds, the invention consists in the novel featureshereinafter set forth, illustrated in the accompanying drawings, andmore particularly pointed out in the appended claims.

Referring to the drawings in which numerals of like character designatesimilar parts throughout both views,

Figure 1 is a vertical sectional view of the improved protecting unit,showing a portion of the motor casing in elevation and Figure 2 is atransverse sectional View taken on line 22 of Figure 1.

In the drawings, referring first to Figure 1, 3 represents a cylindricalmotor casing which is coaxially mounted at the lower end of a pumpingunit (not shown). The lower extremity of the casing 3 is internallythreaded as at 4 to engage the complementary threads of an annularconnecting ring or adapter 5, which serves both as a means forconnecting the casing of the protecting unit as hereinafter described,and as a bearing support for the lower end of the vertical shaft of themotor in casing 3.

The adapter 5 is provided with a centrally disposed boss which forms abearing support 6, preferably connected to the ring of the adapter bymeans of a series of radiating arms 1, the central portion of thesupport 6 being longitudinally drilled to receive an annular bushing 3which serves as a bearing for the lower end 9 of a vertical electricmotor shaft.

Immediately below the motor casing 3, a protecting unit casing I0 iscoaxially mounted, said casing it] being internally threaded at itsupper end as at H, for engagement with complementary threads on theconnecting ring 5. The adjacent ends of the casings 3 and [0 are screwedonto the threads of the ring 5 until they are in abutting relation andthereafter they may be welded as at if! to insure a fixed connection.

The lower extremity of the protecting unit casing I0 is also internallythreaded as at I3, to engage complementary threads on a bottom closuremember M adapted to be inserted in the lower end of the casing Ill. Theclosure member I4 is preferably provided with a concave recess IS in itslower surface and its central portion is drilled as at Hi, to provide acommunicating passageway between the interior of the casing and thesurrounding well fluid. As will be seen from Figure 1, because of theconcave shape of the under surface of the closure member H, thecommunicating passageway is located in a horizontal plane which iselevated with respect to the lower end of the casing, in order toprevent said passageway from becoming clogged by direct contact with thebottom of the well.

The upper portion of the closure member I4 is reduced to form arelatively short, upstanding neck 88, the upper edge of which extendslaterally in an annular flange or shoulder 19, to facilitate themounting of a collapsible diaphragm or breather bag 20.

The bag 20 is normally, substantially domelike in cross section and iscomposed of any suitable flexible material which is not vulnerable toattack by either the oil to be used in the protecting unit or the fluidin which the pumping assembly is submerged. Various materials areadaptable for this purpose and in the preferred form of my invention, Iemploy a material such as neoprene which has the desirable properties offlexibility and will withstand chemical attack. The inverted lower endof the bag 5 is slipped over the upstanding neck [8 of the closure l4and is secured thereto in any suitable manner, such for example, as bythe use of a series of wrappings of waxed linen string 2|, engaging thelower end of the bag below the shoulder 19. This arrangement insures thetight sealed fit of the bag over the shoulder l9 and prevents it fromslipping up off of the neck Hi.

In order to prevent the complete collapse of the bag 20 and to maintaina normally fixed oil reserve capacity within the area of the casing Illwhich surrounds the bag, so as to allow for breathing when the motor isstarted and stopped, I preferably provide a pair of wicket-like supports22 and 23 which are vertically supported within the bag by means ofdrilled holes 24 in the upper surface of the closure neck I8, adapted toreceive the lower ends of the wickets 22 and 23.

As shown in the drawings the wickets are preferably arranged crosswiseor at right angles to one another, to effect a more uniform internalsupport for the bag 20, and they extend vertically to a height toconstantly engage the upper extremity of the bag 20, so as to maintainthe latter in an upright position at all times.

When the various units of the pumping assembly are connected, a suitablelubricating and protecting fluid such as transformer oil, is introducedat the top of the motor unit by means of a filling hole (not shown). Asufficient quantity of protecting fluid is employed to completely fillthat area of the protecting unit II! which surrounds the collapsible bag20 and the area in the motor casing 3 which surrounds the motor,communication between the casings 3 and 10 being afforded by the seriesof spaces between the radial fins or arms 1 of the connecting ring 5and, under static conditions, the weight of this I protecting fluid willcause the walls of the bag 20 to collapse to a certain degree intocontact with the supporting wickets 22 and 23, as shown in Figure 2.

When the motor starts the oil in the casings 3 and I0 gradually expandsand the flexible bag 20 is caused to further collapse at the points between the crossed wickets 22 and 23. Upon stoppage of the motor thefluid in the casing l0 naturally contracts and reduces in volume, andthe water or other surrounding well fluid, which would otherwise bedrawn into the casing and mixed with the oil or protecting fluid, entersthe interior of the bag 20 through passageway 16 and forces the bagoutwardly to compensate for the loss of volume in the cylinder 10.However, this water or surrounding well fluid is retained in the spacewithin the bag 20 and is prevented from contaminating the oil in thecasing, so as to have a deleterious effect upon the motor shaft andultimately the motor structure.

As before explained the wickets 22 and 23 prevent complete collapse ofthe bag 20 and permit breathing not only during the initial starting andstopping operation, but for a prolonged period. When the motor is againstarted the oil in reservoir portion of the cylinder l0, surrounding thebag, naturally expands and with it, the flexible bag 20 collapsesinwardly and under the pressure of the expanding oil, forces the volumeof surrounding fluid within the bag, back into the well, in an amountequal to that previously drawn into the bag 20. It should also be notedthat the higher specific gravity of the water from the well over theoil, creates a slight over-pressure in the oil in the motor whichfurther prevents entrance of the water into the motor.

From the foregoing it is believed that my invention may be readilyunderstood by those skilled in the art, without further description, itbeing borne in mind that numerous changes may be made in the detailsdisclosed, without departing from the spirit of the invention as setforth in the following claims.

I claim:

1. A self-contained motor protecting unit, comprising a cylindricalcasing having means at its upper end for coaxial attachment to the lowerend of a motor housing to form the terminal unit of a submergible,oil-filled, vertical electric motor and pump assembly, means placing theinterior of said casing in communication with the interior of the motorhousing, said casing forming a reservoir for a protecting andlubricating medium, a collapsible diaphragm of substantially dome-shape,arranged concentrically in said casing, in spaced relation to the wallsof the latter, with its interior sealed with respect to the reservoirbut in communication with the fluid surrounding the casing, saiddiaphragm being responsive to variations in the pressure differentialwithin and without said casing, whereby any of said surrounding fluidwhich enters said casing in replacement of lost volume, due tocontraction of said medium, will be confined within said diaphragm untilejected therefrom by expansion of said medium, and a rigid supportingframe, fixed within said diaphragm, to prevent complete collapse thereofunder pressure variations and to thereby maintain a normally fixedreserve breathing capacity within said casing.

2. A protecting unit as claimed in claim 1 wherein said supporting framecomprises at least one vertically disposed wicket.

3. A protecting unit as claimed in claim 1 wherein said supporting framecomprises a pair of transversely crossed, vertical wickets.

4. A self-contained motor protecting unit, comprising a cylindricalcasing having means at its end for coaxial attachment to the lower endof a motor housing to form the terminal unit of a submersible,oil-filled, vertical electric motor and pump assembly; means placing theinterior of said casing in communication with the interior of the motorhousing, the bottom of said casing being closed by a base member, havinga passageway connecting the interior of the casing with the surroundingoil fluid, a domeshaped, collapsible diaphragm, having its lowerextremity concentrically fixed to said base member, surrounding saidpassageway, in spaced relation to the walls of said casing and definingtherein, an outer reservoir for a protecting and lubricating medium anda concentric inner well fluid receiving zone, communicating with thesurrounding well fluid through said passageway, said diaphragm beingresponsive to variations in the pressure differential within and withoutsaid casing, whereby any of said surrounding fluid which enters saidcasing in replacement of lost volume, due to contraction of said medium,will be confined within said diaphragm until ejected therefrom byexpansion of said medium, and a rigid supporting frame, fixed withinsaid diaphragm, to prevent complete collapse thereof under pressurevariations and to thereby maintain a normally fixed reserve breathingcapacity within said casing.

5. A protecting unit as claimed in claim 4, wherein said base member isconcave on its under side and extends into the lower end of said casing,said passageway being disposed above and surrounded by the lowerextremity of the casing.

6. A protecting unit as claimed in claim 4, wherein said base isprovided with an upstanding concentric neck which projects into saidcasing and means for securing said diaphragm to said neck.

'7. A protecting unit as claimed in claim 4 wherein said frame comprisesa wicket, vertically supported on said upstanding neck.

8. A protecting unit as claimed in claim 4 wherein said supporting framecomprises a pair of transversely crossed wickets, vertically supportedon said upstanding neck.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 1,879,628 Mendenhall Sept. 2'7, 1932 2,293,616 Myers Aug. 18,1942

